Evaluating the Circular Defect Detection Capability in Thermography Testing by the Use of Analytical Method

Predicting defect detection capability by means of various non-destructive testing methods in test pieces with different geometries and thermal properties is a challenging issue. In this article, the capability of circular defect detection by thermography testing using analytical method has been investigated. Thermal contrasts produced over the surfaces of circular defects in AA 7075, AISI 1015 and SS316 samples by pulsed thermography (PT), step-heating thermography (SHT) and long pulse thermography (LT) were compared. The thermal contrast of defects in samples with thicknesses of 8, 6 and 4 mm made of AISI 1015 were also compared using the three stimulation methods mentioned. Results showed that PT is the best method in samples with high thermal diffusivity. On the contrary, LPT produces a higher thermal contrast in samples with low thermal diffusivity. Also, by increasing of the thickness, more thermal contrast occurs in all three stimulation methods.